Coherent Electron Control

The “Quantum Measurement Problem” is an unsolved mystery that stops us from bridging the gap between the microscopic and the macroscopic world. To solve this mystery, microscopic objects, electrons, are placed close to a macroscopic everyday world object, a wall. From a practical perspective, it has been proposed that the interaction between electrons and walls limits how small an object an electron microscope can see. If the effects of this interaction can be overcome, we may improve electron microscopes. A second objective of this project is to look at the microscopic, quantum properties of a group of electrons close to each other. Now we have changed the interaction between an electron and a wall to the interaction between electrons. It is predicted that these quantum properties can be used to further improve electron microscopes. The research project provides training for graduate students, undergraduate students and high school students in quantum science, which is an area of national need. The technologies we develop, which include visualization of our work with Augmented Reality headsets, are aimed to strengthen the national economy. The work is done by using electron diffraction from a nanofabricated grating to make a coherent electron quantum wave. By placing a gold coated wall close to the electron wave, we not only decohere the wave, but Caldeira and Leggett also predict an electron energy loss. If we can find the decoherence-energy loss relation, we have demonstrated Quantum Dissipation Theory, and our understanding of the Quantum Measurement Problem has deepened. Using three nanofabricated gratings we have pioneered, we have built an electron-wave, Mach-Zehnder interferometer. With this device we will add even more to our understanding of quantum effects by searching for a newly proposed space-time topology of the celebrated Aharonov-Bohm effect. This quantum effect is especially profound, as it combines relativistic space-time with quantum waves. Finally, a 10-femtosecond laser pulse is used to pull pairs of electrons from a sharp nano-needle. Electrons with the same spin cannot be emitted in the same state, or in other words, cannot be quantum degenerate according to the Pauli Exclusion Principle. This affects the arrival time relation between the electrons. The arrival time cannot be the same, but only when the electrons start very close to each other. Our goal is to push electron-electron quantum degeneracy to a level where it could be used for a new type of imaging: electron-electron quantum correlation imaging. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.